Key performance features required in a golf ball include distance, controllability, durability and feel at impact. Balls endowed with these qualities in the highest degree are constantly being sought. Among recent golf balls, there has emerged a succession of balls which have multilayer structures typically consisting of three pieces (or layers). By having the structure of a golf ball be multilayered, it is possible to combine many materials of different properties, enabling a wide variety of ball designs in which each layer has a particular function to be obtained.
Of these, functional multi-piece solid golf balls having an optimized hardness relationship among the layers encasing the core, such as an intermediate layer and a cover (outermost layer), are widely used. For example, golf balls which have three or more layers, including at least a core, an intermediate layer and a cover, and which are focused on design attributes such as the core diameter, the intermediate layer and cover thicknesses, the deflection of the core under specific loading and the hardnesses of the respective layers, are disclosed in the following patent publications: JP-A 2002-11117, JP-A H9-239068, JP-A H11-104273, JP-A 2001-54588, JP-A 2001-299961, JP-A 2010-188199, JP-A 2010-179119, JP-A 2002-315848, JP-A 2002-345999, JP-A 2004-180822, JP-A 2005-224514, JP-A 2005-224515, JP-A 2006-204908, JP-A 2006-312044, JP-A 2008-119461, JP-A 2009-106739, JP-A 2009-34505, JP-A 2011-120898, JP-A 2011-218161, JP-A 2013-230362 and JP-A 2016-112308.
However, none of the above multi-piece solid golf balls are entirely satisfactory in terms of being able to provide an increased distance by holding down the spin rate on full shots, and moreover achieving both a soft feel and a good durability to repeated impact. In particular, given that, in addition to professional golfers, the golf ball market also includes many mid-level amateur golfers whose head speeds are not as fast as those of professionals and skilled amateurs, there has existed a desire for the development of golf balls which, by being endowed with various high-level performance attributes, including not only a good flight performance on shots with a driver (W#1), but also the ability to exhibit a sufficiently high spin performance on approach shots and a good feel at impact, can satisfy mid-level amateur golfers and are enjoyable to use.